Field of the Invention
The present invention relates to a rod insertion device for inserting a spinal stabilization rod into at least two bone anchors. The device includes a tubular rod guide that allows the spinal stabilization rod to move therethrough, a holding device configured to hold the rod guide, and an adapter configured to be connected to an extension which may be fixed to a receiving part of one of the bone anchors.
Description of the Related Art
It is known in the art to treat fractures of the spinal column, arthrodesis, scoliosis, etc. by stabilizing the spinal column using bone anchors implanted in two or more vertebrae and connecting the same by rigid or dynamically flexible stabilization rods to, for example, define a predetermined relative position and movement tolerance for each of the vertebrae involved. In operation, bone anchors are selectively provided to vertebrae and a stabilization rod is then used (e.g., inserted) to connect each of the bone anchors. Several methods and instruments have been developed to insert a rod into respective rod channels provided in receiving parts of the bone anchors.
U.S. 2013/0096637 A1 discloses an instrument having a main body holding a tubular, curved rod holder which receives a rod. The rod can be advanced through slots of respective spinal implants. An extension at the main body functions as an adapter to connect to a post which is mounted to the receiving part of a spinal implant (e.g., a bone anchor). Keyways provided at the post and extension ensure that the main body attains a predetermined position with respect to the spinal implant. In operation, a handle is used to advance the rod holder with the rod mounted therein through the soft-tissue until a predetermined position proximal to a slot in the spinal implant is reached. Thereby, a set of bearings are provided in the main body which guide the rod holder.
U.S. 2002/0161368 A1 discloses an installation instrument for a connecting element (e.g., a rod) including support arms that respectively connect to anchor extensions mounted to yokes of two adjacent bone anchors. An inserter for the rod is provided as a pivot arm which may pivot in a circular manner about an axis relative to the support arms. As a consequence, the rod is inserted into respective passage ways of the adjacent anchors by the pivoting movement of the inserter.
U.S. Pat. No. 8,105,362 B2 discloses a rod insertion system. Extenders mounted at respective pedicle screw heads are provided with extender heads which are aligned with respect to each other using rod-like alignment members. The alignment members are slidably engaged with a pair of arms which securely connect to an arcuate guide tube. The arcuate guide tube holds an insertion member by which a spinal rod may be advanced through respective passageways of the pedicle screws using a rod insertion probe.
U.S. Pat. No. 7,918,878 B2 discloses a minimally invasive surgical (MIS) system, wherein an inserter formed as a straight rod is held by a guide. The inserter is provided with a connecting member at its tip. The guide is connected to a manipulator assembly extending from a bone anchor, and the guide has an aperture through which the inserter is led such as to deposit the connecting member in an accurate position in passageways of two adjacent bone anchors. The aperture may be opened to release the inserter.